1. Field of the Invention
The present invention relates to an autonomous vehicle which runs autonomously on a set route of travel and a method for autonomously running the autonomous vehicle, and particularly relates to the autonomous vehicle and operation thereof which achieve to run properly and smoothly on the set route according a shape of the route of travel to be passed to reach a final destination as if a vehicle driver were driving a usual automotive vehicle.
2. Background of the art
A Japanese Patent Application First Publication sho 62-162113 published on Jul. 18, 1987 exemplifies one of various kinds of unmanned vehicles which can automatically run without a driver using a photographing device on the unmanned vehicle.
However, in the above-identified Patent Application Publication, a present point at which the unmanned vehicle is placed and a destination cannot be arbitrarily set.
In addition, in another previously proposed unmanned vehicle, a guiding cable is extended along a preset route of travel and the unmanned vehicle is guided along the preset route of travel. When a predetermined signal is transmitted to the guiding cable, a pick up coil installed on the vehicle detects the presence of the predetermined signal on the cable and the vehicle runs on the route of travel, determining a deviation from the preset route of travel.
Furthermore, in another previously proposed unmanned vehicle, an optical reflecting tape made of, e.g., an aluminium tape or polyvinyl tape is adhered to a surface of the route of travel in place of the guiding cable and a projector and light receiver are installed on the unmanned vehicle. Then, a light is projected from the projector and a light reflected on the optical reflecting tape is captured by the receiver. Thus, the unmanned vehicle is guided along the reflecting tape.
However, in a method of guiding the unmanned vehicle along the guiding cable, a large scale of installations of the cable, unmanned vehicles, and route of travel are required and extensions and modifications of the installations become difficult.
In a method of using the optical reflecting tape, a light reflectivity of the tape becomes reduced due to dust and dirt deposited and adhered onto the surface of the tape from the surface of the route of travel. Therefore, a troublesome maintenance operation of cleaning the surfaces of the route of travel and tape is required.
In addition, since the unmanned vehicle is required to run along the cable or tape, an abrupt steering operation is executed when the vehicle runs on a curved line of the route and smooth steering operation is difficult.